[Gem930]

Thanks Richard,
It is a basement SCS unit. The draft is created due to the high flow AC blower unit turning on when I turn on the heat portion of the thermostat. The front thermostat does not do this when I turn heat on. To simplify this explanation when I turn the rear heat on I get hot air from the below the bed radiator and room temp air from the AC vents which is causing the drafty feeling. The air from the AC vents which blows (blower motor only) is not air conditioned it is just room temp. The AC compressors do not turn on, just the blower. After talking with Rudy, it sounds like my rear thermostat may be bad. I’m going to switch the front and rear thermostats and see if the problem moves to the front.